We compare two of Monet’s Rouen Cathedral paintings: In the Morning (1897) and In the Afternoon (1897). In these works, Monet paints not the cathedral, but the time of day. In the first instance, he highlights early morning dew and, in the second, hot afternoon sun. Using details, we examine how light in various atmospheric conditions change the perception of color. We use color contrast theory to explain how Monet responds to color constancy and plays with our perceptual expectations. Color contrast theory explains how through different atmospheric conditions the color of an object appears to change hues. To contrast Monet’s turn-of-the century impressionist works, we introduce Rothko’s Magenta, Black, Green on Orange (1950). Instead of color theory we discuss Rothko’s work in terms of Greenbergian formalism. In which Clement Greenberg says that Abstract Expressionist were striving for purity and autonomy in their compositions. Rothko takes all narrative references out of his work; rather than atmospheric conditions, he focuses on color relationships. We discuss how the magenta, black, and green vibrate in and out on his orange background. We argue that regardless of Rothko’s intensions, his abstractions cause different viewers to make their own interpretation and impose their own cultural expectations on color relationships.